Issue 638616  has been merged into this issue.

We could show a dialog or a toast that a WebAPK has been installed. For long term, we can have a "open" button on the dialog.

+sbirch@: do we show a toast or an app banner with "Open" button?

Another interesting question is: should we do the "installed check" before any "WebAPK-compatible check" for the site? That means, if the url falls into any WebAPK's scope, we won't do a WebAPK-compatible check but pointing the users to the installed WebAPK. In such case, it seems the app banner with "Open" button makes more sense. Any thought?

Xi, just to make sure that I am understanding correctly:

You are suggesting:
If a WebAPK is installed for the site and the user is viewing a page within the WebAPK's scope via Chrome instead of via the WebAPK we should:
- show an app banner with an "Open" button
- ignore any engagement checks

instead of

If a WebAPK is installed for a site and the user is viewing a page within the WebAPK's scope via Chrome instead of via the WebAPK:
The banner does not show
If a user selects "Add to Homescreen" from the menu, we show the banner with an "Open" button

I am suggesting:
If a WebAPK is installed for the site, the user is viewing a page within the WebAPK's scope via Chrome instead of via the WebAPK and the user clicks "Add to Home screen" from menu item:
We should:
- show the app banner infobar with an "open" button

instead of
- show a toast "the webapk has been installed"

Since Chrome won't navigate to WebAPKs when typing from the omni box, it is possible that user is viewing a page within the webapk's scope via Chrome instead of the WebAPK. In such case, do we do the scope check before checking whether the site can be installed as a WebAPK.

As discussed offline, I think we should show the banner with an "open" button to point the user to the installed webapk and don't do the webapk-compatible check in AddToHomescreenManager.

The proposed behavior for the menu makes sense to me. I don't think we should show the banner unless the user taps "Add to home screen" from the menu, however, as there are a variety of normal reasons you might be using a WebAPKed site while browsing and I don't think we need to push them into the WebAPK proper.

If we wanted to get fancy I think the ideal might be to turn "Add to home screen" into "Open <installed site?>" in the menu -- but no need to complicate things for v0 (and we still don't have a good noun to describe it anyways.)

For clarification, when the user clicks the button, I think one of the three scenarios will happen:
1) webapk is not installed,
2) webapk has been installed and up to date,
3) webapk has been installed but is not up to date,

so we change the behavior for scenario 2) & 3) to show an app banner infobar with an "open" button?

zpeng: Your proposal seems reasonable. I think that we should have the same handling for 2 & 3.

I think it is ok to show the "open" button for both 2) and 3). If the installed WebApk is not up to date, the ManifestUpgradeDetector will check whether the WebAPK needs to update once the WebAPK is launched (using clicks the "open" button).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4bb5896ca96a1cda9666cdb33578ff90b53b4c65

commit 4bb5896ca96a1cda9666cdb33578ff90b53b4c65
Author: zpeng <zpeng@chromium.org>
Date: Tue Oct 04 02:42:29 2016

Skip installation process if WebAPK is already installed.

BUG= 638614 

Review-Url: https://codereview.chromium.org/2363183002
Cr-Commit-Position: refs/heads/master@{#422677}

[modify] https://crrev.com/4bb5896ca96a1cda9666cdb33578ff90b53b4c65/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
[modify] https://crrev.com/4bb5896ca96a1cda9666cdb33578ff90b53b4c65/chrome/browser/android/banners/app_banner_infobar_delegate_android.cc
[modify] https://crrev.com/4bb5896ca96a1cda9666cdb33578ff90b53b4c65/chrome/browser/android/shortcut_helper.cc
[modify] https://crrev.com/4bb5896ca96a1cda9666cdb33578ff90b53b4c65/chrome/browser/android/shortcut_helper.h